Extendable shower arm



FIG. 1 is a perspective view of an extendable shower arm showing my new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a front end view thereof; and,

FIG. 7 is a rear end view thereof. 

The ornamental design for an extendable shower arm, as shown and described. 